Verifying the Geographical Origin and Authenticity of Greek Olive Oils by Means of Optical Spectroscopy and Multivariate Analysis.

Georgia Sofra-Karanti,Aikaterini Zoumi,Renate Kontzedaki,Emmanouil Orfanakis,Aggelos Philippidis,Michalis Velegrakis,Katerina Stamataki

doi:10.3390/molecules25184180

Abstract

Olive oil samples from three different Greek regions (Crete, Peloponnese and Lesvos) were examined by optical spectroscopy in a wide spectral region from ultraviolet to near infrared using absorption, fluorescence and Raman spectroscopies. With the aid of machine learning methods, such as multivariate partial least squares discriminant analysis, a clear classification of samples originating from the different Greek geographical regions was revealed. Moreover, samples produced in different subareas of Crete and Peloponnese were also well discriminated. Furthermore, mixtures of olive oils from different geographical origins were studied employing partial least squares as a tool to establish a model between the actual and predicted compositions of the mixtures. The results demonstrated that optical spectroscopy combined with multivariate statistical analysis can be used as an emerging innovative alternative to the classical analytical methods for the identification of the origin and authenticity of olive oils.

Highlights

Olive oil is a fruit juice produced in a completely natural way from olives (Olea europaea), without the use of chemical solvents or other additives
We investigated the classification of olive oil samples using optical spectra for various spectral regions from ultraviolet (UV) to near-Infrared (NIR), and fluorescence and Raman spectroscopic data
This study shows that visible absorption and/or Raman spectroscopy in combination with multivariate statistical analysis can distinguish olive oils produced in different geographical regions

Summary

Introduction

Olive oil is a fruit juice produced in a completely natural way from olives (Olea europaea), without the use of chemical solvents or other additives. The protective role of the phenolic components of olive oil is well known [2]. The increased demand of olive oil may lead to illegal activities, such as false declaration of geographical origin and counterfeiting authenticity. The geographical indications of PDO (protected designation of origin), PGI (protected geographical indication) and TSG (traditional specialty guaranteed) are used for the commercial protection of a product originating from a specific region and following a traditional production process. PDO includes agricultural products that are produced in a specific geographical area. PGI includes products linked to a geographical area. At least one of the production stages occurs in that area. TSG includes products that have been created using traditional materials or traditional production methods [4]

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